Blueberry (Vaccinium corymbosum) is an economically important fruit crop that is native to North America. Other members of the Vaccinium genus, including cranberry (V. macrocarpon) and lingonberry (V. vitis-idaea), also have significant economic importance due to the use of their fruits in food production, pharmaceuticals and health care products. Fresh market production of blueberries in the United States was valued at $781 million in 2011 and was planted over 77,000 acres, and has significantly grown in the last 20 years. In addition to its commercial value, blueberries are prized for their positive health benefits. Blueberries contain high levels of antioxidants, which can reduce inflammation caused by chronic diseases such as the antioxidant resveratrol, which has been linked to a decreased risk of cancer and heart disease. Iridoids are another class of known pharmacologically important compounds that have recently been found in blueberries and cranberries. Iridoids are present in over 15 plant families and are potent natural products with a wide range of biological activities in humans including, anticancer, antibacterial and anti-inflammatory. Despite their known human health benefits, iridoids are a neglected component of blueberry research. Therefore, the broad, long-term objective of the proposed work is to improve the biochemical, molecular, and genetic understanding of iridoid production in blueberry to enable improved access to these compounds for future clinical research. To reach these objectives, this proposal has three specific aims: 1) survey iridoid compounds in a diversity panel of Vaccinium spp. using biochemical analyses to characterize the range of iridoid compounds, 2) identify the genes underlying iridoid biosynthesis in blueberry through genomic, transcriptomic and bioinformatics analyses, and 3) perform functional characterization of the tailoring enzymes involved in the specific iridoid biosynthetic pathway in blueberry. Overall, this project will provide new insights into iridoid production in blueberries and related Vaccinium species, and provide an understanding of the genetic basis for iridoid metabolism in an economically important fruit crop.